Printing machine

ABSTRACT

A printing machine arranged so that the two kinds of operations, i.e., progressive shifting in position of the printing hammer over the rows of printing types and the printing actions by this hammer are carried out by separate drive sources, respectively, and that the hammer module is moved along a rectilinear rod, whereby high speed printing is feasible and highly legible images of the printed types as well as very clear and pleasant distribution of the printed images of types can be obtained.

United States Patent [191 -Matsuzawa" 1 PRINTING MACHINE [75] Inventor: Nobuyoshi Matsuzawa, Tokyo,

Japan [73] Assignee: Kabushiki Kaisha Koparu,

Tokyo-t0, Japan [22] Filed: July 19, 1972 [21] Appl. No.1 273,128

[30] Foreign Application Priority Data July 23, 1971 Japan. 46/65367 [52] US. Cl. 197/49, 10l/93 C [51] Int. Cl B4lj 9/04, B4lj H24 [58] Field of Search..-.'. 101/93, 49

[56] References Cited UNlTED. STATES-PATENTS 2,438,071 3/1948 Page et al. 101/93 C 2,843,243 7/1958 Masterson l0l/93- 2,919,005 12/1959 Beattie et al...v 197/49 3,227,259 l/l966 Howard 197/49 [111 3,795,300 [[4 1 Mar.5,1974

3,364,852 l/l968 Ragcn 101/93 C 3,424,291 H1969 Marion 1 197/49 3,429,414 2/1969 Bradbury 197/82 3,526,309 9/1970 Marion ct al. 197/49 Primary Examiner-Ernest T. Wright, Jr.

Assistant ExaminerPau l J. Hirsch Attorney, Agent, or Firm-Cushman, Darby &

Cushman [57] ABSTRACT A printing machine arrangedso that the two kinds of operations, i.e progressive shifting in position of the printing hammer over the rows of printing types and the printing actions by this hammer are carried out by separate drive sources, respectively, and that the hammer module is moved along a rectilinear rod, whereby high speed printing is feasible and highly legible images of the printed types as well as very clear and pleasant distribution of the printed images of types can be obtained. 7

l 3 Claims, 2 Drawing Figures BACKGROUND OF THE INVENTION a. Field of the Invention The present invention concerns a printing machine, and more particularly, it pertains to a line printer arranged to print types successively by shifting the position of the printing hammer progressively along the printing drum.

b. Description of the Prior Art In known line printers, the shifting in position of the hammer module over the rows of printing types was conducted by rotating a threaded shaft having a spiral groove in which a pin of the hammer module engages. However, such a known line printer of this arrangement had the drawbacks represented by the wide intervals between the printed images of types and by the high cost of manufacture of the printer. Also, in the line printer having the aforesaid arrangement, the bringing back of the hammer module tothe starting position following the completion of printing of a given single line was performed by first detaching said pin off the spiral groove and then by relying on the restoring force of a spring. Accordingly, the position to which the hammer module is returned is not necessarily constant for all such scanning cycles. As a consequence, it could occur that the printing action by the hammer was not performed at the required proper positions so that there often were the cases in which the images of the printed types were irregular in position on the recording paper, thus giving the reader an illegible impression.

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a printing machine arranged so that the printing hammer module is moved intermittently for a constant amount at a time along the type-carrying drum, thereby reducing the intervals between the printed images of types.

Another object ofthe present invention is to provide a printing machine having the aforesaid features and arranged so that the drive means for the printing hammer and the drive means for shifting the position of the printing hammer module are provided separately relative to each other so that'there are produced, at high speed, clear images of print on a recording paper and also that leaping of rows of printing types can be easily performed whenever required.

Still another object of the present invention is to provide a printing machine having the foregoing features and arranged so that when the printing operation of a given single line is completed, the printing hammer will be returned always and positively to the exact predetermined starting position.

A further object of the present invention is to provide a mechanism of conveying the printing hammer module, which permits the processing of its parts to be performed easily and permits the manufacture of the parts at a low cost.

These and other objects as well as the attendant advantages of the present invention will become apparent by reading the following detailed description of an embodiment of the invention when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of the essential parts of the printing machine according to the present invention.

FIG. 2 is a fragmentary plan view taken along the line II-II in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIGS. 1 and 2, reference numeral 1 represents a main body frame. Numeral 2 represents a belt applied to a pulley fixed to the shaft of a drive motor not shown. Numeral 3 represents a shaft rotatably mounted on said frame 1. Numeral 4 represents a pulley fixed on said shaft 3 and having the belt 2 applied thereto. Numeral 5 represents a printing type carrying drum fixed on said shaft 3. Numerals 5a, 5b, 5c, 5n represent rows of characters formed on the circumferential surface of said drum 5. Numerals 6 and 7 represent a roller and a gear fixed on said shaft 3, respectively, and intended for feeding a recording paper. Numeral 8 represents a hammer module. Numeral 8a represents a hammer driven by a drive means such as an electromagnet not shown. Numerals 8b and represent screws attached onto the hammer module 8, respectively. Nume'ral 9 represents a supporting shaft supported on said frame 1 and receives said hammer module 8 so that the latter is movable thereon. Numeral 10 represents a spring for conveying the hammer module 8.

One end of this spring l0 is attached, by the screw 8b, tothe hammer module 8, and the other end is fixed to a part of the main body after being turned over inwardly of the mechanism in F IG. 1 via a guide member not shown. I

Numeral 11 represents a shaft rotatably mounted on said frame 1. Numeral 12 represents a gear attached to one end of said shaft 11 via a clutch means 13 such as a known spring clutch and also coupled to the gear 7 via a gear 30. Numeral 13a represents. a stopper groove formed on the spring clutch l3. Numeral 14 represents an electromagnet attached to the frame 1 via a spacer 15. Numeral 16 represents a pole-contacting lever swingably attached to the york portion of the electromagnet-14. This pole-contacting lever 16 has, at one end, a stopper hook 16a extending into the stopper groove 13a of the spring clutch 13, and has a polecontactingportion 16b formed at the other end.

Numeral 17 represents a pulley rotatably attached to a supporting member 18 which, in turn, is fixed to the frame 1. Numeral 19 represents a take-up spool. Ratchet teeth 19a are formed on the periphery of one end of this spool 19 and a flange 19b is formed on the other end thereof. This spool-19 is rotatably mounted on the shaft 11. Numeral 20 represents a cam lever rotatably attached at one end to a shaft 19c extending on both sides of the flange 19b of the spool 19. This cam lever 20 has at its intermediate portion a cam face 200 and has an engaging portion 20b formed at the free end thereof. Also, a stud 19d extends from one side of the flange 19b of the spool 19. A spring 21 is applied between said stud 19d and the free end of the cam lever 20. Numeral 22 represents a stopper which is engageable with the engaging portion 20b formed at the free end of the cam lever 20.-This stopper 22 extends from the main body. Numeral 23 represents a cam plate which has a cam face 23a. This cam plate 23 is fixed to said shaft 11 in such a way that its cam face 23a is engageable with the cam face 20a of the cam lever 20. Numeral 24 represents a rope having one end anchored to the screw 80 of the hammer module 8, the other end of which rope is fixed to the spool 19. Numeral 25 represents a drive means such as an electromagnet which is attached to the frame 1 via a spacer 26. Numeral 27 represents a pole-contacting lever, at one end of which is formed a pawl portion 27a meshing with the ratchet teeth 19a of the spool 19 and at the other end is formed a pole-contacting portion 27b. This pole-contacting lever 27 is swingably attached to the york of the electromagnet 25.

Numeral 28 represents a spring for urging the polecontacting lever 27 in one direction. Numeral 29 represents an adjusting screw for adjusting the distance between the magnetic pole of the electromagnet 25 and the pole-contacting portion 27b of the pole-contacting lever 27. A recording paper and an ink ribbon which are not shown are interposed between the printing type carrying drum and the hammer 8a.

Description will hereunder be made on the functions of the aforesaid arrangement.

By transmitting rotation to the pulley 4 and accordingly to the shaft 3 via the belt 2 from a motor not shown, the gear 12 is rotated via the drum 5 and the gear 7.

On the other hand, the hammer 8a of the hammer module 8 which is at the position shown in FIG. 1 is actuated, an electromagnet (not shown) which is incorporated in the hammer module 8 and which energizes by a pulse signal generated in synchronism with the rotation of the drum 5, to print the types on the first line.

In immediate succession thereto, a pulse signal is applied to the electromagnet 25. Thus, as will be understood clearly from FIG. 2, the pole-contacting lever 27 which is at the position illustrated is caused to swing, with the result that its pawl portion 27a is momentarily disengaged from its meshing with the ratchet tooth 19a of the spool 19. As a consequence, the spool 19 is urged to rotate counter-clockwise in FIG. 2 by the tension of the conveying spring 10. However, subsequent to the responding action of the pole-contacting lever 27 to said pulse signal, this lever 27 will immediately act in such a way as to cause, instantaneously by the force of the spring 28, the pawl portion 27a to mesh again with a ratchet tooth 19a. As a result, the spool 19 will eventually rotate through an amount corresponding to a single tooth among the ratchet teeth 19a. Accordingly, the hammer module 8 will also be moved toward the left in FIG. 1 for a distance corresponding to said amount of a single tooth and stops at this position. This amount of movement covered by the hammer module 8 corresponds to a a type column. More specifically, in the state of the mechanism shown in FIG. 1, the hammer 8 moves to the position corresponding to the row of characters shown at 5b and stops thereat and is thus rendered to be ready to print the character in this row. In this way, characters of the respective rows are printed successively one after another, so that the hammer module 8 moves from its position shown in FIG. 1 towards the left side progressively, and that the spool 19 is also rendered to a state in which it has rotated counter-clockwise from its position shown in FIG. 2. During this part of operation, the cam lever of the spool 19 is released from the stopper 22. As a result, the cam face 20a of this cam lever 20 will be brought into the path of travel of the cam face 23a of the cam plate 23.

When printing of a single line has thus been completed, let us assume that a pulse signal for bringing back the hammer module 8 is applied to the electromagnet 14. Whereupon, the pole-contacting lever 16 will instantaneously swing, causing its stopper hook 16a to disengage from the stopper groove 13a of the spring clutch 13. Accordingly, this spring clutch will exert its clutching action so that the rotation of the normally rotating gear 12 is transmitted to the shaft 11. During this part of operation, the cam plate 23 which is fixed to this shaft 11 will owing to the engagement between the cam faces 20a and 23a cause the cam lever 20 to rotate integrally with the shaft 11. As a consequence, the spool 19 is caused to rotate to wind the rope 24 therearound. Accordingly, the hammer module 8 is quickly returned to its position shown in FIG. 1 by overcoming the tension exerted by the spring 10. During this part of operation, the engaging portion 2( )b of the cam lever 20 is again brought into contact with the stopper 22, so that as shown in FIG. 2 the cam face 20a is disengaged from the cam face 23a. As a result, the spool 19 is urged to rotate counter-clockwise by the tension of the spring 10. At this moment, however, that pawl portion 27a of the pole-contacting lever 27 which has till then been sliding over the ratchet teeth during the winding of said rope 24 is brought into mesh with the ratchet tooth 19a, so that the spool 19 is arrested in its counterclockwise rotation, causing the respective members to rest at the positions illustrated.

In this way, the respective mechanisms are rendered to their initial state, ready for further printing operation whenever a pulse signal is applied to the respective electromagnets.

I claim:

1. A printing machine, comprising:

a main body frame;

a type-carrying drum rotatably supported on said frame;

a printing hammer module arranged in adjacent relation to said drum and capable of moving along said drum;

a printing hammer housed within said printing hammer module;

a spring having one end coupled to said main body frame and the other end coupled to said printing hammer module to urge said hammer module in its feeding direction;

a driving member rotatably supported on said frame;

a clutch means connected to said driving member and operative upon completion of the printing action for each type line;

a rope having one end coupled to said printing hammer module;

' a rotary shaft having a cam member forming a first cam face coupled thereto and capable of rotating together with said driving member when said clutch means is operated;

a rotatable spool connected to the other end of said rope to wind up said rope;

a flange formed on said spool;

a cam lever rotatably mounted on said flange and forming a second cam face engageable with said first cam face to rotate said spool when said rotary shaft is rotated;

6 a stopper secured to said frame and capable of engagmove by the extent corresponding to a type coling with said cam lever to disengage the engageumn; ment between said first and second cam faces when a first drive means arranged adjacent to said lever said rope is wound up against the force of said member for controlling the engagement and disenspring by the engagement of said first and second 5 gagement of said lever member with and from said cam faces and when said hammer module is reratchet teeth. turned to'its starting position; 2. A printing machine according to claim 1, in which ratchet teeth formed on the periphery of said spool; said first drive means contains an electromagnet. a lever member pivotably supported on said frame 3. A printing machine according to claim 1, in which and engageable with said ratchet teeth to cause 10 said clutch means is comprised of a spring clutch coaxisaid spool to rotate by the extent corresponding to ally arranged with said rotary shaft and an electromaga single tooth of said ratchet teeth upon completion net-driving means for controlling the action of said of the printing action by said printing hammer and spring clutch.

to thereby cause said printing hammer module to 

1. A printing machine, comprising: a main body frame; a type-carrying drum rotatably supported on said frame; a printing hammer module arranged in adjacent relation to said drum and capable of moving along said drum; a printing hammer housed within said printing hammer module; a spring having one end coupled to said main body frame and the other end coupled to said printing hammer module to urge said hammer module in its feeding direction; a driving member rotatably supported on said frame; a clutch means connected to said driving member and operative upon completion of the printing action for each type line; a rope having one end coupled to said printing hammer module; a rotary shaft having a cam member forming a first cam face coupled thereto and capable of rotating together with said driving member when said clutch means is operated; a rotatable spool connected to the other end of said rope to wind up said rope; a flange formed on said spool; a cam lever rotatably mounted on said flange and forming a second cam face engageable with said first cam face to rotate said spool when said rotary shaft is rotated; a stopper secured to said frame and capable of engaging with said cam lever to disengage the engagement between said first and second cam faces when said rope is wound up against the force of said spring by the engagement of said first and second cam faces and when said hammer module is returned to its starting position; ratchet teeth formed on the periphery of said spool; a lever member pivotably supported on said frame and engageable with said ratchet teeth to cause said spool to rotate by the extent corresponding to a single tooth of said ratchet teeth upon completion of the printing action by said printing hammer and to thereby cause said printing hammer module to move by the extent corresponding to a type column; a first drive means arranged adjacent to said lever member for controlling the engagement and disengagement of said lever member with and from said ratchet teeth.
 2. A printing machine according to claim 1, in which said first drive means contains an electromagnet.
 3. A printing machine according to claim 1, in which said clutch means is comprised of a spring clutch coaxially arranged with said rotary shaft and an electromagnet-driving means for controlling the action of said spring clutch. 